1. Field of the Invention
The present invention relates to an information processing system comprising a first information processing apparatus and a second information processing apparatus compatible with the first information processing apparatus. The present invention particularly relates to a control of an execution, on the second information processing apparatus, of software created for the first information processing apparatus.
2. Description of the Background Art
There is a known conventional entertainment apparatus having compatibility with an existing entertainment apparatus (e.g., Japanese Laid-Open Patent Publication No. 2001-314644). The conventional entertainment apparatus (hereinafter, referred to as a superordinate model) has two operation modes, i.e., a first mode and a second mode. The first mode is a normal mode to perform a normal operation of the apparatus, and the second mode is a compatibility mode to perform an operation on the assumption of compatibility with another model. The superordinate model usually starts up and operates in the normal mode. However, the superordinate model shifts to the compatibility mode when executing a title (software) dedicated for an existing entertainment apparatus (hereinafter, referred to as a subordinate model).
The superordinate model includes first processor means, which has an MPU (main processing unit) and a GP (graphics processor), and second processor means which has an IOP (input/output subprocessor). In the normal mode, the first processor means acts as a main CPU and a rendering processor, and the second processor means acts as an I/O processor. In the compatibility mode, on the other hand, the second processor means acts as a main CPU, and the first processor means acts as a rendering processor. Here, the second processor means is a same processor core as a CPU of the subordinate model. Therefore, the second processor means is able to execute a program code which is prepared for the CPU of the subordinate model, and perform same operations as those performed by the CPU of the subordinate model.
[Patent Document 1] Japanese Laid-Open Patent Publication No. 2001-314644
However, the above entertainment apparatus disclosed in the Japanese Laid-Open Patent Publication No. 2001-314644 has the following problem. When the superordinate model executes, in the compatibility mode, the title (software) of the subordinate model, the same processor core as that of the subordinate model is used as the main CPU. Accordingly, the superordinate model is able to perform the same operations as those of the subordinate model, and thus compatibility is sufficiently obtained. However, when operating the software of the subordinate model in the compatibility mode, the superordinate model is unable to use functions newly added to the superordinate model.